In keeping with the recent increase of the amount of information to be processed in information telecommunication equipment, electronic circuits for signal transmission have come to be adapted to increasingly higher frequency level with a growing number of wiring connections. The trend in the design of a package for housing electronic components is also toward adaptability to high frequency ranges and an increase in the number of terminals for providing connection between inside and outside of the package. FIG. 8 shows an example of an electronic apparatus constructed by placing an electronic component within a package in a hermetic manner. Specifically, FIG. 8(a) is a plan view of the package and FIG. 8(b) is a structural diagram showing a cross section of the package.
In the package shown in FIG. 8, an input-output terminal 103 comprises a ceramic-made first flat-plate portion 103a formed with a first line conductor 111 extending between an outer one side of a topside frame 102 and an inner other side of the frame 102; and a ceramic-made second flat-plate portion 103b formed with a second line conductor 112 which extends in parallel with the first line conductor 111 so as to avoid overlap with the first line conductor 111 in a vertical direction (for example, refer to (Japanese Unexamined Patent Publication JP-A 2004-356391).
In this way, by arranging the first line conductor 111 and the second line conductor 112 in an alternating manner so as to avoid mutual overlap in the vertical direction, even if the number of the line conductors 111 and 112 is increased, it never occurs that the input-output terminal 103 has an unduly large size.
However, in recent years, electronic components have come to be operated with electric signals in increasingly higher frequency ranges. Should electric signals in high frequency ranges be transmitted through the first line conductor 111 and the second line conductor 112, there will arise the problem that the input-output terminal of conventional design and the package using it fail to serve the intended purposes.